_once_stub.c revision 281887 
1/*-
2 * Copyright (c) 2009 Hudson River Trading LLC
3 * Written by: John H. Baldwin <jhb@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: head/lib/libc/gen/_once_stub.c 281887 2015-04-23 14:22:20Z jhb $");
30
31#include "namespace.h"
32#include <pthread.h>
33#include "un-namespace.h"
34#include "libc_private.h"
35
36/* This implements pthread_once() for the single-threaded case. */
37static int
38_libc_once(pthread_once_t *once_control, void (*init_routine)(void))
39{
40
41	if (once_control->state == PTHREAD_DONE_INIT)
42		return (0);
43	init_routine();
44	once_control->state = PTHREAD_DONE_INIT;
45	return (0);
46}
47
48/*
49 * This is the internal interface provided to libc.  It will use
50 * pthread_once() from the threading library in a multi-threaded
51 * process and _libc_once() for a single-threaded library.  Because
52 * _libc_once() uses the same ABI for the values in the pthread_once_t
53 * structure as the threading library, it is safe for a process to
54 * switch from _libc_once() to pthread_once() when threading is
55 * enabled.
56 */
57int
58_once(pthread_once_t *once_control, void (*init_routine)(void))
59{
60
61	if (__isthreaded)
62		return (_pthread_once(once_control, init_routine));
63	return (_libc_once(once_control, init_routine));
64}
65